Critical care medicine
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Critical care medicine · Jan 1984
Case ReportsLocal lung ventilation in critically ill patients using nonradioactive xenon-enhanced transmission computed tomography.
Nonradioactive xenon is sufficiently radiodense to increase the density of gas-containing lung as seen in a computed tomography (CT) scan. Subtraction of a baseline CT scan from the xenon-enhanced CT scan can accentuate gas space differences by subtracting fixed tissue densities. ⋯ The xenon CT scan, thus, provides more precise information about distribution of ventilation than planar radiogas techniques. The technical aspects of application to a critically ill patient and the mathematical basis of the technique are presented.
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Critical care medicine · Jan 1984
Comparative StudyPercutaneous transtracheal jet ventilation for cardiopulmonary resuscitation: evaluation of a new jet ventilator.
This study compared percutaneous transtracheal jet ventilation (PTJV) at a frequency (f) of 20/min, with high-frequency positive-pressure ventilation (HFPPV) at f of 60/min, and endotracheal intubation and intermittent positive-pressure ventilation (ET IPPV) at f of 10/min in apneic dogs. Fifty-four emergency medicine trainees (EMTs) attempted PTJV via a 14-gauge Angiocath attached to a hand-held jet ventilator, f of 20/min, and ET IPPV using an Ambu bag, f of 10/min. Twenty-nine other EMTs attempted cricothyrotomy using a prototype nonkinkable catheter (Arrow) and a new jet ventilator, Bronchovent, f of 60/min, equipped with a pressure sensor which stops ventilation at pressures greater than 20 cm H2O. ⋯ There was a higher equipment failure rate (catheter kinking and dislodgment) in the PTJV group. In the HFPPV group, the Bronchovent's pressure-limiting sensor stopped ventilation when the catheter was kinked or out of position, reducing the extent of subcutaneous emphysema and barotrauma. With further catheter improvements, HFPPV Bronchovent may offer a safe and reliable method of ventilating patients during CPR in the field.
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Critical care medicine · Dec 1983
Comparative StudyHemodynamic comparison of albumin and hydroxyethyl starch in postoperative cardiac surgery patients.
The hemodynamic effects of 2 plasma volume expanders were compared in postoperative open heart surgery patients. Albumin 5% (A) or hydroxyethyl starch 6% (HES) solutions were infused according to indications based on cardiac index (CI) and pulmonary wedge pressure (WP), and their effects evaluated by physiologic profile measurements. Both groups demonstrated significant increases with volume infusion in CI (A from 2.37 to 2.84; HES from 1.97 to 2.49 L/min X m2) and WP (A from 9.4 to 13.7 mm Hg; HES from 11.9 to 13.2 mm Hg). ⋯ No significant difference for any variable was demonstrated between the A and HES groups. In the volume used, from 250 to 750 ml, HES caused no bleeding abnormalities. HES is as effective as A as a plasma volume expander in postoperative cardiac surgery patients.
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Critical care medicine · Nov 1983
Left ventricular regional myocardial blood flows during controlled positive pressure ventilation and positive end-expiratory pressure in dogs.
A decrease in myocardial blood flow (MBF) has been suggested as a possible cause for the depression of left ventricular function during mechanical ventilation. In 8 dogs, hemodynamic effects of controlled mechanical ventilation with 15 cm H2O of PEEP or (CPPV15) were compared to controlled mechanical ventilation without PEEP (IPPV). Addition of PEEP caused a significant decrease in left ventricular epicardial, midwall (p less than .01) endocardial and septal (p less than .05) blood flows. ⋯ Left ventricular myocardial oxygen consumption (LVMVO2) and coronary sinus oxygen content (Ccso2) also did not show any significant change. Pulmonary vascular resistance (PVR) increased significantly (p less than .01). The observed decrease in MBF during PEEP therapy may be due to shift of the interventricular septum, reflexly mediated coronary vasoconstriction, or decreased net coronary filling pressure.